10/14/2026 updated
100 % available
Senior Full-Stack Engineer | Fintech, AI & SaaS | TypeScript, Node.js, React
Ronse, Belgium
Only remote
BSc Computer Science, University of Amsterdam, 2016JavaScriptApplication Programming Interfaces (APIs)Software as a ServicePostgreSQLNode.jsNext.jsTypeScriptBackendAWS ECSStripeFull Stack DevelopmentGraphQLApi DesignFintechTerraform
TypeScript & JavaScript Development
Extensive expertise in TypeScript and JavaScript, including React, Next.js and Node.js, with proven delivery of scalable customer dashboards and public REST APIs used by over 120 integrating customers.
Cloud Infrastructure & DevOps
Strong command of AWS, Docker, Terraform and GitHub Actions, including the migration of 14 services to AWS ECS with Terraform, reducing monthly cloud costs by 27% and implementing CI/CD pipelines with 85% test coverage.
API Design & Backend Engineering
Deep experience in designing and building REST and GraphQL APIs, webhook systems and high-throughput backend services using Node.js and PostgreSQL, handling 2M+ transactions per month.
Database Engineering & Performance Optimization
Solid background in PostgreSQL and Redis, including query index optimization that reduced p95 API latency from 820 ms to 310 ms and Redis caching on high-traffic endpoints.
Payment & Fintech Integrations
Hands-on experience with Stripe and Adyen APIs, as well as building and maintaining reconciliation services for payments platforms processing millions of transactions monthly.
Python Development
Working knowledge of Python as part of a broader technology stack, applied in engineering and automation contexts within fintech and SaaS environments.
OAuth2 & Security
Practical experience with OAuth2 for authentication and authorization flows, supporting secure B2B SaaS platforms and customer-facing integrations.
Technical Leadership & Mentoring
Experience leading small engineering teams, mentoring mid-level engineers, managing on-call rotas and driving incident response time improvements from 40 to 15 minutes.
Extensive expertise in TypeScript and JavaScript, including React, Next.js and Node.js, with proven delivery of scalable customer dashboards and public REST APIs used by over 120 integrating customers.
Cloud Infrastructure & DevOps
Strong command of AWS, Docker, Terraform and GitHub Actions, including the migration of 14 services to AWS ECS with Terraform, reducing monthly cloud costs by 27% and implementing CI/CD pipelines with 85% test coverage.
API Design & Backend Engineering
Deep experience in designing and building REST and GraphQL APIs, webhook systems and high-throughput backend services using Node.js and PostgreSQL, handling 2M+ transactions per month.
Database Engineering & Performance Optimization
Solid background in PostgreSQL and Redis, including query index optimization that reduced p95 API latency from 820 ms to 310 ms and Redis caching on high-traffic endpoints.
Payment & Fintech Integrations
Hands-on experience with Stripe and Adyen APIs, as well as building and maintaining reconciliation services for payments platforms processing millions of transactions monthly.
Python Development
Working knowledge of Python as part of a broader technology stack, applied in engineering and automation contexts within fintech and SaaS environments.
OAuth2 & Security
Practical experience with OAuth2 for authentication and authorization flows, supporting secure B2B SaaS platforms and customer-facing integrations.
Technical Leadership & Mentoring
Experience leading small engineering teams, mentoring mid-level engineers, managing on-call rotas and driving incident response time improvements from 40 to 15 minutes.
Experience
Professional experience5 - 10 years
Freelancer since2020
Languages
EnglishNative speakerFrenchGoodDutchNative speaker
Project history
Rebuilt the reconciliation service in Node.js/PostgreSQL, cutting mismatches from 3.1% to 0.4% and saving finance about 30 hours a week. Reduced p95 API latency from 820 ms to 310 ms by adding query indexes and a Redis cache. Led the migration of 14 services to AWS ECS with Terraform, cutting monthly cloud cost by 27%. Mentored 3 mid-level engineers and ran the on-call rota, bringing incident response time from 40 to 15 minutes.
Built the customer dashboard in React/TypeScript; adoption reached 78% of active accounts within 6 months. Designed the public REST API and webhook system used by 120 integrating customers. Introduced CI/CD with GitHub Actions and 85% test coverage, shortening release cycles from 2 weeks to 2 days.
Delivered 20+ client web apps in React and Node.js, from scoping to deployment.